Sounds like what you need is to bust up the reading material into some kind of sets. Then offer some books of the books that defined the genre.
So here are like three suggestions at least for scifi that I can name off the top of my head. (I have read all these works. And there are probable so many more that I don't name.)
Cyberpunk = The Shockwave Rider by John Brunner, (1975 book, introduced the concept of a computer worm.) Neuromancer by William Gibson. (1984, defines many concepts that are used on the internet today.) Or Cryptonomicon by Neal Stephenson (1999, Just a damn good read, will let others define this one.)
Modern SciFi (Defined as post WWII) = Stranger in a Strange Land by Robert A. Heinlein (1961, gives us the wonderful word... grok.) Ender's Game by Orson Scott Card. (1985, a very definitive work.) The Left Hand of Darkness by Ursula K. Le Guin (1969, can't leave out a work by a very well known female writer.)
Classic Scifi = These ones everyone knows. 20 Thousands Leagues Under the Sea by Jules Verne (1870, Fun book... bonus points if you can find what parts are copies of that one nature book.) War of the Worlds by H. G. Wells (1898, Alian invastion! 19th century style) The Call of Cthulhu by H. P. Lovecraft. (1928, short story that gives us Cthulhu.)
Best I can do at the time. Feel free to add more.